Britbike forum Forums Thread Like Summary - BSA Metal Tank Mount

I think this type of metal tank center mounting is a thing of beauty. 9 different pieces.

Just saying

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Gordon: I am with you on this one. It is very clever without being too heavy and it isolates the tank quite well from the frame.

Gordo

8 pieces? Don't see them (but then I've never used one of these fashionable road-apple devices)... could you show how it all works?

Tres chic. It certainly is pretty classy...

How many engineer/designers muddle-forked over this, while happily continuing to give us those miserable 68 footpeg mounts for 69?

I've never been able to make this work with that spacer over or under the big rubber O-ring; with the spacer in there, the fore and aft trim pieces don't fit right in the cup. Everything seems to fit fine without the spacer, and the ends stopped breaking off the trim pieces.

Also, it's important that the nut tightens against the sleeve and pins the sleeve to the frame. This should not be a problem if you have all the correct parts (including the correct rubbers under the tank). If the sleeve is too short, the cup will be stressed and will break away from the chrome ring.

and that my friend. is an indicator of the downfall of Brit bike dominance. too many parts to do a simple job

mine broke 44 years ago and a friend brazed it for me. its been fine ever since.

didnt have the ring over thr doughnut when i bought it and i never knew they existed until now

mine doesnt bottom out, or at least ive never tightened it until it did. maybe thats why it works.

I like the solution, but have constant problem with threaded part sticking up to much above the nut, preventing rubber cover to seat comfortably in it's place.. Perhaps should use some washers under the spacer to rise all the assembly a bit?
But my tank is home market 4 gallon for a twin

I was wrong; I finally found a photo of the top of a tank; the center chrome piece has two spigots, fore and aft, just like my '67 chrome tank. The FS in question is listed as a "concourse restoration", so I have to believe it's correct.

By the way, I was able to source the trim strips for my '67 tank, either from British Cycle Supply or Walridge Motors. That was a while ago though, and I don't know if the '69 FS bit is the same.

I just looked at photos of '69 Firebird Scramblers, and the tanks look like the one in your photo - trim strip rear only, Monza cap in center. I can't see the tops of the tanks, but I would bet there's only one "spigot" on that center trim piece.

*NOTE: Gordon, I posted the following before seeing the above photos.*

"I tried taking a photo of a damaged cup but just couldn't get the details. Basically it had been ripped apart. Someone probably left the spacer out having no idea what it's purpose was."

By "spacer", I assume you mean the sleeve that goes over the bolt. Been there, tried DYI solutions and ruined a couple of cups before biting the bullet and sourcing the correct parts. By the way, that extra washer goes at the bottom of the sleeve, and is important to make up the correct length.

"I have a tank that I would love to add trim to but have no idea what it came off. I'm 99% sure it wasn't a unit single."

What bike are you using this on? If the tank doesn't have a ridge down the center, it will not accommodate the trim strips. My knowledge is confined to '67 twin cyl. chrome tank. Without trim strips, I would think the cup with the "spigots" fore and aft would look odd. Tanks without chrome trim had a different sort of mount, some where the rubber plug pushes directly into the tank.

Commentary: With all the mounts "correct" (including having a proper bushing in the bottom "strap"), I've ridden for many years without breaking anything. HOWEVER... Even though I have the proper molded rubber behind the tank badges, and even though I used rubber O-rings under the heads of the single mounting screws, I'm starting to see a small spider crack around the screw on one side. Lovely as the Lucite badges are, I guess I understand why BSA went to the die-cast badges.

Firebirds have been seen all red with knee grips and also with chrome panels from original (I had one with the chromed panels also). The channels should be same for A65 and B series. they are quite wide even compared to some of the A65 tanks and have rubber mounts to suit.

The last tank in primer is a 70 A65 Lightning tank. - that should have chromed panels also.

The cap is identical to one Gary E has on one of his 67 or 68 off road A series bikes? (Im sure he will chime in?), the commonly used cap had a square button and was probably easier to press with a gloved finger. the type pictured was often used on some cars - so I beleive.

Gordon, the red and white paint scheme also suggests a '69-'70 Firebird Scrambler home market tank. Didn't you say the channel is wider than your B25 tank?

The filler cap looks stock. Later A65 chrome tanks ('69, '70, not sure about '68) had flip up caps like that.

Gordon, could that be a '69 A65 FS home market tank? Monza filler caps were used on later A65 chrome tanks, but over to the side.

I don't think that center trim piece is correct for that tank.

Anyone have a screwdriver "from the Steve McQueen collection", for less than $1,000 bucks?

They are both A 65 Fire bird tanks
The B44 tank does not have 2 carb cut aways underneath cos it aint got 2 carbs
Very common to find them on B44 roadsters because the std tank is just too small for any serious trip .
Riding is no fun if you are consistantly looking for a fuel station .

Gordon, i appreciate your reply to the "Steve McQueen screwdriver" joke.

It's like the "original George Washington hatchet," the one that the head was replaced three times and the handle replace five.
The prices are similar to the ones the EBAY seller from Appleton, Wisconsin, puts on any common small part he attempts to sell on that site.

I am no expert on BSA gas tanks, but if one is a bit wider than the other, and both properly fit, I'd choose the wider one, just for the extra gas capacity..

I have yet to see one of these tanks without the cutaways for 2 carbs. Im sure theres also a lot more B25/B44 bikes than 1969/70 FS's

The one I fitted to my lightning as mentioned above was 2.25 British Gallons (I think thats about 2.75 US Gallons), The 70 Lightning tank i beleive is somewhere between 3-3.5 British Gallons, my Father has one for his bike but we have never been filled it up.

I've heard that the two cut-aways at the bottom rear of the tank were to clear fuel lines on the twins.

But is it possible they are actually there to clear the rear downward frame tubes where they branch off from the top main frame tube?

Been a long time since I laid a spanner on one but from memory ( always risky ) the twin tank has an equal cut out on both side of the tank to clear the head & the fuel taps splay out
Singles have the head cut out mostly on one side with the fuel taps further forward and vertical .
A65 tanks fit nicey on B44's with thicker rubbers but B44 tanks will not fit well on A65's as they have to be mounted higher off the engine.
Small tanks high above the engine seems to be a popular USA thing as a lot of the US imported A65's seem to have single tanks fitted to them.
The cut aways allow for a smooth curve of the throttle cable
Without them the cable would need a right angle end on the adjuster

Gordon non-ethanol is $4.79 a gallon here in Gasolovakia